If a light is shined at a mirror, is all of the light being reflected back?

Question

or is some absorbed?

Answer 1

a small amount is absorbed in household mirrors, however there does exist situations where a perfect mirror is achieved, such as the refection you see at shallow angles from underwater in a phenomenon known as total internal reflection.

Answer 2

I doubt that any mirror would be a perfect reflector for all spectrums of light. I would think there would have to be small amounts being absorbed.